Geo-casting allows an individual to communicate with others in a specific geographic area, and has been a long sought capability for a number of applications. For instance, motor carrier operators may wish to contact all of their drivers threatened by inclement weather to warn them of the approaching storm or to order that they seek shelter. For another example, emergency response officials may wish to contact all cell phone owners within the area of a disaster to relay instructions and to obtain information regarding the nature and scope of the emergency.
Prior art technologies fail to adequately provide geo-casting capability for several reasons. Broadcasting a message, for any one to receive, may compromise confidential or sensitive information. Moreover, some of the intended recipients may be out of reception range and may not receive the message. Even recipients within reception range may not receive the message due to noise, interference or other inabilities of the communication system to deliver the message (e.g. out of date addresses for mobile recipients). Multicasting, in contrast, might ensure that all intended recipients (and only the intended recipients) receive the message. However, the overhead and time required to set up a multi cast may prevent time critical messages from arriving in a timely fashion. The latter disadvantage being especially critical in real time applications subject to rapidly evolving conditions.
Additionally, the routing of real time communications may be impractical when the recipients may move relative to the area of interest. For instance, transmitting a message from a transmitter dedicated to the area of interest may still miss some intended recipients because the recipients may have moved out of range of the transmitter even within the area of interest because of interference from foliage, \land forms, buildings, or other obstructions. It also may inadvertently transmit to recipients outside of the area of interest. In the alternative, a recipient may have moved into the area unbeknownst to the sender, thus being overlooked for inclusion in the communication, particularly where the message is not broadcast.
Accordingly, a need exists for a telecommunications system that operates to better ensure that all intended recipients, and only the intended recipients, within a given geographic area receive specific messages.